Q. Do you agree or disagree with each of the subsequent statements? Briefly explain your answers and illustrate each with supply and demand curves. (Please remember to illustrate each with supply and demand curves, as this is illustrate what I'm struggling with)

a- The price of a good rises, causing the demand for another good to fall. The goods are therefore substitutes.

b- A shift in supply causes the price of a good to fall. The shift must have been an increase in supply.

c- During 2007, incomes rose sharply for most Americans. This change would likely lead to an increase in the prices of both normal and inferior goods.

d- Two normal goods cannot be substitutes for each other.

e- If demand increases and supply increases at the same time, price will clearly rise.

f- The price of good X falls. This causes an increase in the price of good Y. goods X and Y are therefore complements.